Things you Should know about your Android

Android Versions (2009 - 2015)

Android phones have really become common because of the functions they provide, because of the updates that are provided  & because of the huge App store that we have :)
Another reason for the popularity of this OS is because it's Open Source (i.e the source code is released by google), hence it being a playground for developers to MOD (modify) the OS.

But how many of us are actually aware of the little basics about our phone ?
Here is an attempt by me to make you aware of few basic things or terms used in the Android community.


1.FIRMWARE :- In the past all electronic gadgets used to have a Micro-controller with a program on it which was specific to the device and was never upgraded. This so called 'embedded  systems' had this software known as FIRMWARE.

2.ROM :- ROM basically means Read Only Memory i.e. you can read but cannot write/modify the Contents. Mobile developers used to develop software for the phones and this software was nothing to do with the user [user was not having access to modify], so people used to call that software a ROM image. This continued and still people call the Mobile software or OS as ROM.

3.STOCK ROM :- The ROM image provided by the company for that particular device is called STOCK ROM. This ROM is usually is digitally signed by the company. The STOCK ROM are usually very stable, but consume a lot of space and have many system apps which are unnecessary [known as bloatware].

4.CUSTOM ROM :- This is basically the Modification of the Stock ROM, developers remove the bloatware, give themes, change the usage of the RAM, Improve battery etc. Since the custom ROM are developed by people, stability is a big issue. Updates depend on whether the developer will work on it or not. There might be lot bugs or none [depending on developer].
Example:- CyanogenMod, a well recognized ROM made by quiet a good developers is well know for its stability and extra functions. [It's updated frequently because of vast community of developers working for cyanogenMod]

5.ASOP :- About 1-2 times a year, the vanilla Android operating system (known as AOSP, or the Android Open Source Project) is internally developed, then released to the public, by Google. They provide the source code to anyone who wants to download it, the ASOP is used to make device specific STOCK ROM.

6.OTA :- Over-the-Air, transmitted via Wi-Fi or mobile network, as opposed to downloaded to the phone via USB cable (e.g. OTA update).
OTA update is available even if we unlock bootloader or root phone. Phone is eligible for OTA update from company till no modification is done to system files :)

7. BRICK :- a device that no longer functions, generally caused by a failed firmware or SPL update. Since the device no longer works as intended, it is often referred to as a "brick" or "paper-weight", since that is all it is good for.

8.BOOTLOADER :- The "bootloader" is the name of the program that first loads when you press the "on" button (or power button) on your device. It helps to load the Kernel file, Ramdisk and the main android OS.  
A "locked bootloader" has a restriction on what it will load based on digital signatures given by manufactures. Bootloader's are locked for security reasons, we cannot install custom OS or Modify the system until the bootloader is locked.
Unlocking the bootloader is possible through the use of the fastboot tool, available for free via the android sdk, and causes an immediate wipe of user data, to prevent an attacker from using this same tool to gain access to user data.
Unlocking Bootloader voids the manufacture's warranty. 
Locked Bootloaders only allow the official system images signed by Manufacturer, hence OTA is available even when Bootloader is Locked :)
Many developers of free and open general-purpose computers look at locked bootloaders as a kind of "system bug" or design flaw, because they restrict the freedom of the owner of the device to replace the operating system with one which may be newer, better, faster, more secure, etc. 

9.KERNEL :- Kernel is a file which is written in a low level programming language, it is the file which has the information about the device processor. Kernel file establishes the connection between the OS and the processor, its a link between hardware and software.
Google writes the OS in general and not device specific, so Kernel is something each Device manufacturer must provide. Changes in Kernel results into change in voltages, current flow etc, hence MOD of Kernel is the most Risky job and might lead to a Hard Brick.
KERNEL are device specific. SO DON'T USE ANY KERNEL AVAILABLE, IT MAY BRICK YOUR DEVICE.

10.FASTBOOT MODE :- Fastboot is a protocol that can be used to re-flash partitions on your device (update the flash file system in Android devices).It is an alternative to the Recovery Mode for doing installations and updates.
While in fastboot, you can modify the file system images from a computer over a USB connection. Fastboot mode can start on your device even before Android loads, even under the circumstance when Android isn’t installed at all. And because of that, fastboot mode is useful for quick-updating the firmware, without having to use a recovery mode. In fact, it’s the preferred way to initially install the recovery image. 
It can also be used for developer operations. Things like erasing partitions and overriding kernel command line options can be done.

11.RECOVERY MODE :- Recovery is a limited boot mode, independent of your normal Android operating system. In recovery, you can backup, restore, install packages, wipe data, and do limited troubleshooting of Android. The feature set available depends on the specific recovery installed. In general, stock recoveries (which come pre-installed on your device) are the most limited. They typically only allow manufacturer updates to be performed and remain mostly invisible to the end user.
Examples :- CWM [clock work mod], TWRP [Team Win Recovery Project] etc.

12.FLASHING :- The process of applying a firmware image (or ROM) to a device. It generally entails a very specific order of steps.

13.ROOTING / ROOT ACCESS :- Obtaining root ("administrator", or "full") access to the device. This means you can mount its internal memory partition as read/write, which lets you do various things: have USB or Wi-Fi tethering, uninstall applications you otherwise can't uninstall, install applications that need root access, disable the camera shutter sound (simply by deleting the shutter sound file), overclock or underclock the CPU, install and boot Debian, and so on. Installing CyanogenMod roots the device in the process. The "Superuser" app controls what applications may gain root privileges.

• So now first step for any user is to unlock the bootloader, which gives us a access to modify system. Now user can get the root access and use STOCK ROM or flash a Custom Recovery. Using Custom Recovery we can flash any ROM that we want.

• Basically Fastboot mode helps us flash the Recovery Image or STOCK ROM. Recovery helps us with the rest.

• Your Phone may not switch on, may stuck at logo, may not show anything this situation is called as soft brick.

• Till the time fastboot mode is accessible there is no need to worry. Phone can be recovered through fastboot mode.

1.MOUNT :- In recovery mode, mount indicates selection of that particular partition example :- mount system indicates the partition is now ready to be accessed.

2.DALVIK CACHE :- The dalvik-cache directory holds all of the pre-compiled .dex files created from installed apps. These files are static and do not change unless the app is updated.

3.CACHE :- Temporary files that your app creates for its working. Has nothing to do with your data in the app, cleaning this will not affect your saved data in the app.

4.DATA :- All the users information, his preferences, saved files together make up the data. Cleaning the data will result in user's loss in information or saved files related to the app.

5.CLEAN FLASH :-  When you are flashing a completely new ROM or you face bootloop then a clean flash is recommended. In clean flash we mount system, then wipe data, internal storage, cache, dalvik cache, system. This results in no OS in device and a complete deletion of data and media files in internal storage.

6.DIRTY FLASH :- When a new version of same ROM is present, we can just wipe cache, dalvik cache and install new updated OS. This does not delete your data or media files.

No changes will be there except for the system.

7.CUSTOM KERNEL :- Custom kernel has following benefits :-

- the minimum and maximum frequencies that the CPU can scale up or down to

- how busy the CPU should be before it enables extra cores that it normally has disabled to save battery

- the frequency the CPU should boost to whenever it detects touch input (to ensure a smoother wake up)

- the CPU governor (which determines how quickly it tends to ramp up the frequency or not)   that should be used

- change the voltage of the CPU during all possible frequencies

- the maximum frequency of the GPU

- enable USB fast charge (for USB 3.0 ports)

- configure the I/O scheduler that is used.

8.GOVERNOR :- A governor is actually nothing more then a behavior profile for your CPU, the governor will tell the CPU exactly what to do in what situation.

Default types :-

– ondemand, the overall default CPU governor worldwide. Basically just ramps up your CPU speed to max freq when just pushing the screen once, then lowering it back to the minimal cpu freq (somewhat smart, but not optimized at all).

– performance just stays at the max CPU freq all the time (horrible for your battery).

– powersave stays at the min CPU freq all the time (resulting over the top lag).

– conservative is somewhat adjusted to use less power, but that’s also very notable in performance.

– userspace is a governor that needs to be completely configured manually, the default setting is the same as powersave, it will stay at your min CPU freq when not configured. (this governor is rarely used)

9. I/O SCHEDULER :-

Globally Governors and Schedulers are the same, they both provide a way how the system should work. but on Schedulers it’s all about the Input/Output datastream except the CPU settings. the I/O Schedulers decide how the upcoming I/O activity is being scheduled.

The standard schedulers are“noop” and “cfq” etc.

10. NANDROID BACKUP :- Custom recovery provides us with a function of backup. Nandroid backup means a image of the phone is created and saved as zip. The data, files, system everything is stored. Reflashing of this backup is done using custom recovery. Restoring backup puts your phone in the same state as it was when you took the backup. It will restore all your messages, saved games everything as it was before.

 

IT IS ALWAYS RECOMMENDED TO TAKE A NANDROID BACKUP OF YOUR STOCK ROM OR A STABLE SYSTEM BEFORE MAKING ANY CHANGES.